A method and an according network structure for providing connectivity of devices to a radio access network are known from prior art. There are various use cases wherein at least two devices are connectable to a radio access network and wherein said at least two devices are members of a group of devices within a wireless local network. Further, a direct connection between said devices within the wireless local network is possible.
3GPP LTE networks aim to provide broadband connectivity to multiple users enhancing the service quality. Among the different services offered by LTE, new evolving services that take advantage of the LTE ubiquitous coverage involve no human participation and hence introduce new requirements beyond the traditional ones. Such requirements are different because of the plurality of Machine Type Communication, MTC, devices and the need to transmit small data at infrequent periods. 3GPP has already specified the network architectures for supporting such MTC devices and services, while currently is exploring ways to optimize the network usage for supporting large number of MTC devices, see 3GPPTS 23.682.
In particular, it is estimated that large numbers of MTC devices are affiliated with a single MTC user. The MTC user owns a MTC Server which is allied with a number of MTC devices. This server and devices are connected through a packet switched network owned by a mobile network operator via an Access Point Name, APN, using Gi interface. Typically, if there are ‘n’ numbers of MTC users who own ‘m’ numbers of MTC devices (n×m) number of devices need to transmit small data, and for each individual transmission the radio and S1 bearer needs to be re-established when moving from ECM_IDLE to ECM_CONNECTED state per device.
Such a process can cause congestion considering the associated signaling required in combination with the high number of MTC devices, which may try to access the network almost simultaneously: (1) to attach to the network or (2) to activate/modify/deactivate a connection. Use cases are given in 3GPP TS 22.368.
When many or each device needs to send small amounts of data, then the Radio Resource Control, RRC, connection setup, radio bearer setup and S1 bearer setup generate more signaling than the size of the user data payload that has to be transmitted.
This results in a large amount of network resources necessary for the connectivity of the devices and for the communication of the devices with elements of the radio access network.
In the paper “A Group Based Communication Scheme Based on the Location Information of MTC Devices in cellular Networks,” authors K. Lee and J. Shin focused on a group based communication where this scheme groups a number of connections that are triggered by closely located UEs if a certain application of the UEs triggers a number of connections to request the same user data. For an example, a number of audiences in a concert hall may try to receive a pamphlet as they enter the hall. Or like a certain bunch of closely located devices upgrading the firmware. In these cases, this group base communication is used to utilize the downlink data transmission. So this scheme is effectively providing a multicasting solution, which groups UEs based on location information that is made available to the network via complementary MTC devices.
In WIPO Patent Application WO/2012/041363, radio bearer sharing scheme for wireless machine type communication, MTC, especially for a group of MTC devices with small traffic in the same cell. A group of MTC devices served in the same cell is treated as one user equipment. An MTC device ID is used to uniquely identify such an MTC device on the MTCu interface with a base station in a cell. All the MTC devices in a group share the same radio network identifier and the MTC group identifier, and can be distinguished by the device index in the group. The base station allocates one radio bearer over the MTCu interface for the small sessions of the devices, which have similar QoS requirements (QCI parameter and Layer 2 parameters) and the same MTC server. The data transmission scheduling information is signalled from the base station to the MTC devices in the same group, which may be achieved without over the air signalling if the timing of the UL signal is linked to a corresponding DL transmission interval. Then the devices transmit data packets one by one accordingly. Within the MTCu DRB, the compressed ID is added into the PDCP PDU header to identify the packets belonging to different MTC devices. Only updates need to be communicated between the MTC devices and the base station in the case that the device members of an MTC group change.
In U.S. Patent Application Publication No. U.S. 2012/0296968, a method is proposed to group M2M devices together and to associate such groups of devices with a M2M gateway that provides connectivity towards the network and can also identify devices within the group. The proposed scheme is static, having a fixed M2M gateway. Our invention adopts the concept of M2M gateway in terms of connectivity but in our proposal M2M gateway is the one that uses the virtual bearer and can change dynamically. In addition our scheme introduces the concept of virtual bearer that can be shared by all devices in the group and also introduces security measures.
In “Towards Ubiquitous Massive Accesses in 3GPP Machine-to-Machine Communications,” published in IEEE Communications Magazine, Vol. 49, No. 4, April 2011, authors S-Y. Lien, K-C. Chen, and Y. Lin describe prior M2M grouping methods focusing on efficient radio resource management, grouping M2M Devices according to their QoS requirements. Their purpose is to organize M2M Devices into QoS-specific groups based on expected packet arrival rates and maximum tolerable delays to be capable to estimate and schedule radio resource accordingly with the objective to allocate adequate resource for M2M services without disturbing other applications.